84 THE FOEAMINIFEEA 



"J"-shaped, on the inner surface of the shell. Lias 

 to Beceiit. 



Examples. — B. coviata,lircidy, 'Rep."Chall."' vol. 

 ix. 1884, p. 144, pi. iii. figs. 9 a, b. 



This is a pretty, striated form of Biloculina, 

 which was brought to light by the ' Porcupine ' and 

 ' Challenger ' expeditions. It is rarely that we find 

 Biloculince with a surface ornamentation so well 

 marked as this, and the present species is also 

 striking on account of its fairly large dimensions. 

 It measures nearly 1 mm. in length. B. comata 

 generally affects depths ranging from 300 to 600 

 fathoms. Becent. (Plate 2, figs. I and J.) 



B. ringens^ Lamarck sp. {MilioUtes ringens), 

 'Annales du Museum,' vol. v. 1804, p. 351, No. 1; 

 1807, vol. ix. pi. xvii. fig. 1. 



This is one of the earliest known species to such 

 pioneers as Soldani, who in 1795 described it under 

 the name of 'Frumentaria Quit la.' Lamarck, who 

 adopted the Linnean system of nomenclature, gave 

 it the name of MilioUtes ringens, the generic name 

 being used at the time equally for the biloculine, 

 the triloculine, and the quinqueloculine types. 

 B. ringens is a typical form of the genus, and 

 exhibits a medium inflation of the chambers, 

 B. depressa being narrower in section and B. 

 buUoides more globose. 



B. ringens makes its first appearance, so far as 

 we know, in the Tertiary beds (Middle Eocene) of 

 the Paris Basin, and it also occurs in strata of 

 Miocene, Pliocene, and Pleistocene ages. 



